/*******************************************************************************
 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/

package org.jbox2d.common;

/** This is the viewport transform used from drawing. Use yFlip if you are drawing from the top-left corner.
 * 
 * @author Daniel */
public interface IViewportTransform {

	/** @return if the transform flips the y axis */
	boolean isYFlip ();

	/** @param yFlip if we flip the y axis when transforming */
	void setYFlip (boolean yFlip);

	/** This is the half-width and half-height. This should be the actual half-width and half-height, not anything transformed or
	 * scaled. Not a copy. */
	Vec2 getExtents ();

	/** This sets the half-width and half-height. This should be the actual half-width and half-height, not anything transformed or
	 * scaled. */
	void setExtents (Vec2 extents);

	/** This sets the half-width and half-height of the viewport. This should be the actual half-width and half-height, not
	 * anything transformed or scaled. */
	void setExtents (float halfWidth, float halfHeight);

	/** center of the viewport. Not a copy. */
	Vec2 getCenter ();

	/** sets the center of the viewport. */
	void setCenter (Vec2 pos);

	/** sets the center of the viewport. */
	void setCenter (float x, float y);

	/** Sets the transform's center to the given x and y coordinates, and using the given scale. */
	void setCamera (float x, float y, float scale);

	/** Transforms the given directional vector by the viewport transform (not positional) */
	void getWorldVectorToScreen (Vec2 world, Vec2 screen);

	/** Transforms the given directional screen vector back to the world direction. */
	void getScreenVectorToWorld (Vec2 screen, Vec2 world);

	Mat22 getMat22Representation ();

	/** takes the world coordinate (world) puts the corresponding screen coordinate in screen. It should be safe to give the same
	 * object as both parameters. */
	void getWorldToScreen (Vec2 world, Vec2 screen);

	/** takes the screen coordinates (screen) and puts the corresponding world coordinates in world. It should be safe to give the
	 * same object as both parameters. */
	void getScreenToWorld (Vec2 screen, Vec2 world);

	/** Multiplies the viewport transform by the given Mat22 */
	void mulByTransform (Mat22 transform);
}
